The nitridation of ZnO nanowires

ZnO nanowires (NWs) with diameters of 50 to 250 nm and lengths of several micrometres have been grown by reactive vapour transport via the reaction of Zn with oxygen on 1 nm Au/Si(001) at 550°C under an inert flow of Ar. These exhibited clear peaks in the X-ray diffraction corresponding to the hexagonal wurtzite crystal structure of ZnO and a photoluminescence spectrum with a peak at 3.3 eV corresponding to band edge emission close to 3.2 eV determined from the abrupt onset in the absorption-transmission through ZnO NWs grown on 0.5 nm Au/quartz. We find that the post growth nitridation of ZnO NWs under a steady flow of NH₃ at temperatures ≤600°C promotes the formation of a ZnO/Zn₃N₂ core-shell structure as suggested by the suppression of the peaks related to ZnO and the emergence of new ones corresponding to the cubic crystal structure of Zn₃N₂ while maintaining their integrity. Higher temperatures lead to the complete elimination of the ZnO NWs. We discuss the effect of nitridation time, flow of NH₃, ramp rate and hydrogen on the conversion and propose a mechanism for the nitridation.     

Large-scale and uniform preparation of pure-phase wurtzite GaAs NWs on non-crystalline substrates

One of the challenges to prepare high-performance and uniform III-V semiconductor nanowires (NWs) is to control the crystal structure in large-scale. A mixed crystal phase is usually observed due to the small surface energy difference between the cubic zincblende (ZB) and hexagonal wurtzite (WZ) structures, especially on non-crystalline substrates. Here, utilizing Au film as thin as 0.1 nm as the catalyst, we successfully demonstrate the large-scale synthesis of pure-phase WZ GaAs NWs on amorphous SiO₂/Si substrates. The obtained NWs are smooth, uniform with a high aspect ratio, and have a narrow diameter distribution of 9.5 ± 1.4 nm. The WZ structure is verified by crystallographic investigations, and the corresponding electronic bandgap is also determined to be approximately 1.62 eV by the reflectance measurement. The formation mechanism of WZ NWs is mainly attributed to the ultra-small NW diameter and the very narrow diameter distribution associated, where the WZ phase is more thermodynamically stable compared to the ZB structure. After configured as NW field-effect-transistors, a high I_ON/I_OFF ratio of 10⁴ − 10⁵ is obtained, operating in the enhancement device mode. The preparation technology and good uniform performance here have illustrated a great promise for the large-scale synthesis of pure phase NWs for electronic and optical applications.     

A catalyst-free growth of aluminum-doped ZnO nanorods by thermal evaporation

The growth of Al:ZnO nanorods on a silicon substrate using a low-temperature thermal evaporation method is reported. The samples were fabricated within a horizontal quartz tube under controlled supply of O₂ gas where Zn and Al powders were previously mixed and heated at 700°C. This allows the reactant vapors to deposit onto the substrate placed vertically above the source materials. Both the undoped and doped samples were characterized using scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) measurements. It was observed that randomly oriented nanowires were formed with varying nanostructures as the dopant concentrations were increased from 0.6 at.% to 11.3 at.% with the appearance of ‘pencil-like’ shape at 2.4 at.%, measuring between 260 to 350 nm and 720 nm in diameter and length, respectively. The HRTEM images revealed nanorods fringes of 0.46 nm wide, an equivalent to the lattice constant of ZnO and correspond to the (0001) fringes with regard to the growth direction. The as-prepared Al:ZnO samples exhibited a strong UV emission band located at approximately 389 nm (E _g  = 3.19 eV) with multiple other low intensity peaks appeared at wavelengths greater than 400 nm contributed by oxygen vacancies. The results showed the importance of Al doping that played an important role on the morphology and optical properties of ZnO nanostructures. This may led to potential nanodevices in sensor and biological applications.     

Gas sensing properties of conducting polymer/Au-loaded ZnO nanoparticle composite materials at room temperature

In this work, a new poly (3-hexylthiophene):1.00 mol% Au-loaded zinc oxide nanoparticles (P3HT:Au/ZnO NPs) hybrid sensor is developed and systematically studied for ammonia sensing applications. The 1.00 mol% Au/ZnO NPs were synthesized by a one-step flame spray pyrolysis (FSP) process and mixed with P3HT at different mixing ratios (1:1, 2:1, 3:1, 4:1, and 1:2) before drop casting on an Al₂O₃ substrate with interdigitated gold electrodes to form thick film sensors. Particle characterizations by X-ray diffraction (XRD), nitrogen adsorption analysis, and high-resolution transmission electron microscopy (HR-TEM) showed highly crystalline ZnO nanoparticles (5 to 15 nm) loaded with ultrafine Au nanoparticles (1 to 2 nm). Film characterizations by XRD, field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy, and atomic force microscopy (AFM) revealed the presence of P3HT/ZnO mixed phases and porous nanoparticle structures in the composite thick film. The gas sensing properties of P3HT:1.00 mol% Au/ZnO NPs composite sensors were studied for reducing and oxidizing gases (NH₃, C₂H₅OH, CO, H₂S, NO₂, and H₂O) at room temperature. It was found that the composite film with 4:1 of P3HT:1.00 mol% Au/ZnO NPs exhibited the best NH₃ sensing performances with high response (approximately 32 to 1,000 ppm of NH₃), fast response time (4.2 s), and high selectivity at room temperature. Plausible mechanisms explaining the enhanced NH₃ response by composite films were discussed.     

Tuning of structural,optical, and magnetic properties of ultrathin and thin ZnO nanowire arrays for nano device applications

One-dimensional (1-D) ultrathin (15 nm) and thin (100 nm) aligned 1-D (0001) and (0001¯) oriented zinc oxide (ZnO) nanowire (NW) arrays were fabricated on copper substrates by one-step electrochemical deposition inside the pores of polycarbonate membranes. The aspect ratio dependence of the compressive stress because of the lattice mismatch between NW array/substrate interface and crystallite size variations is investigated. X-ray diffraction results show that the polycrystalline ZnO NWs have a wurtzite structure with a = 3.24 Å, c = 5.20 Å, and [002] elongation. HRTEM and SAED pattern confirmed the polycrystalline nature of ultrathin ZnO NWs and lattice spacing of 0.58 nm. The crystallite size and compressive stress in as-grown 15- and 100-nm wires are 12.8 nm and 0.2248 GPa and 22.8 nm and 0.1359 GPa, which changed to 16.1 nm and 1.0307 GPa and 47.5 nm and 1.1677 GPa after annealing at 873 K in ultrahigh vacuum (UHV), respectively. Micro-Raman spectroscopy showed that the increase in E₂ (high) phonon frequency corresponds to much higher compressive stresses in ultrathin NW arrays. The minimum-maximum magnetization magnitude for the as-grown ultrathin and thin NW arrays are approximately 8.45 × 10⁻³ to 8.10 × 10⁻³ emu/g and approximately 2.22 × 10⁻⁷ to 2.190 × 10⁻⁷ emu/g, respectively. The magnetization in 15-nm NW arrays is about 4 orders of magnitude higher than that in the 100 nm arrays but can be reduced greatly by the UHV annealing. The origin of ultrathin and thin NW array ferromagnetism may be the exchange interactions between localized electron spin moments resulting from oxygen vacancies at the surfaces of ZnO NWs. The n-type conductivity of 15-nm NW array is higher by about a factor of 2 compared to that of the 100-nm ZnO NWs, and both can be greatly enhanced by UHV annealing. The ability to tune the stresses and the structural and relative occupancies of ZnO NWs in a wide range by annealing has important implications for the design of advanced photonic, electronic, and magneto-optic nano devices.     

Gallium hydride vapor phase epitaxy of GaN nanowires

Straight GaN nanowires (NWs) with diameters of 50 nm, lengths up to 10 μm and a hexagonal wurtzite crystal structure have been grown at 900°C on 0.5 nm Au/Si(001) via the reaction of Ga with NH₃ and N₂:H₂, where the H₂ content was varied between 10 and 100%. The growth of high-quality GaN NWs depends critically on the thickness of Au and Ga vapor pressure while no deposition occurs on plain Si(001). Increasing the H₂ content leads to an increase in the growth rate, a reduction in the areal density of the GaN NWs and a suppression of the underlying amorphous (α)-like GaN layer which occurs without H₂. The increase in growth rate with H₂ content is a direct consequence of the reaction of Ga with H₂ which leads to the formation of Ga hydride that reacts efficiently with NH₃ at the top of the GaN NWs. Moreover, the reduction in the areal density of the GaN NWs and suppression of the α-like GaN layer is attributed to the reaction of H₂ with Ga in the immediate vicinity of the Au NPs. Finally, the incorporation of H₂ leads to a significant improvement in the near band edge photoluminescence through a suppression of the non-radiative recombination via surface states which become passivated not only via H₂, but also via a reduction of O₂-related defects.     

Effects of Aliovalent Anion Substitution on the Electronic Structures and Properties of ZnO and CdS

Aliovalent anion substitution in ZnO, CdS, and related materials brings about drastic changes in their electronic structure and properties, making them colored, with a narrow band gap. Progressive substitution of N and F in ZnO leads to the formation of Zn₂NF, with complete replacement of O with N and F. The band gaps of Zn₂NF and O-doped Zn₂NF are smaller than the band gap in ZnO, because N 2p states create a new sub-band above the valence band. Band-edge energies of these compounds are thermodynamically favorable for water splitting. First-principles calculations of P- and Cl-substituted CdS and ZnS show the presence of a band just above the valence band, due to the p orbitals of the trivalent dopant, resulting in a noticeable reduction in the band gap of these materials. Such substitution of anions can be quite effective in engineering the valence band, and hence, in tuning the related properties of materials. Complete substitution of S with P and Cl in CdS should result Cd₂PCl, but the resulting material is Cd₂PCl_1.5 or Cd₄P₂Cl₃. Cd₄P₂Cl₃ shows a band gap of 2.36 eV and a photoluminescence band at 580 nm. First-principles calculations show it to be an effective photocatalyst for water splitting; it is shown experimentally to exhibit photocatalytic hydrogen evolution in the presence and absence of a sacrificial agent. Moreover, resilience to photocorrosion is a unique property of Cd₄P₂Cl₃.     

Effect of Calcination Temperature on the Structural and Optical Properties of (ZnO)0.8 (ZrO2)0.2 Nanoparticles

Calcination temperature has influenced the structural and optical features of nanocrystalline (ZnO)_0.8 (ZrO₂)_0.2 series. Indeed, at present, general research in the approach to synthesis of (ZnO)_0.8 (ZrO₂)_0.2 nanoparticles by combustion using zinc nitrate hexahydrate (Zn (NO₃)₂·6H₂O) and zirconium (11) nitrate pentahydrate (Zr (NO₃)₂·5H₂O) is still in its infancy. A Thermogravimetric (TG) assessment was performed to determine the precursor of the conduction. Characterizations such as energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–Visible, Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL) spectroscopy were carried out. The crystallite size of the binary oxides (ZnO)_0.8 (ZrO₂)_0.2 on the maximum expansion of ZnO–ZrO₂ nanoparticle was studied using Scherrer’s equation. Due to calcination, significant modifications were observed in terms of the size of the particles, the absorption spectra, and the intensity of the photoluminescence. In the XRD result, an increment in crystallinity was observed from 10.20 nm to 28.00 nm while the FTIR findings showed the removal of the polymer as well as the presence of nanoparticles metals. The optical band gap results indicated a decline in energy band gap between (3.27 and 3.12) eV for (ZnO)_0.8 and (4.89–4.51) eV for (ZrO₂) _0.2 nanoparticles. A photoluminescence result showed two individual peaks at 655 nm (1.89 eV) and 715 nm (1.73 eV) respectively. The study also showed the application which can be a suitable choice to be used in solar cell applications.

     

Cu-doped ZnO nanorod arrays: the effects of copper precursor and concentration

Cu-doped ZnO nanorods have been grown at 90°C for 90 min onto a quartz substrate pre-coated with a ZnO seed layer using a hydrothermal method. The influence of copper (Cu) precursor and concentration on the structural, morphological, and optical properties of ZnO nanorods was investigated. X-ray diffraction analysis revealed that the nanorods grown are highly crystalline with a hexagonal wurtzite crystal structure grown along the c-axis. The lattice strain is found to be compressive for all samples, where a minimum compressive strain of −0.114% was obtained when 1 at.% Cu was added from Cu(NO₃)₂. Scanning electron microscopy was used to investigate morphologies and the diameters of the grown nanorods. The morphological properties of the Cu-doped ZnO nanorods were influenced significantly by the presence of Cu impurities. Near-band edge (NBE) and a broad blue-green emission bands at around 378 and 545 nm, respectively, were observed in the photoluminescence spectra for all samples. The transmittance characteristics showed a slight increase in the visible range, where the total transmittance increased from approximately 80% for the nanorods doped with Cu(CH₃COO)₂ to approximately 90% for the nanorods that were doped with Cu(NO₃)₂.     

Effects of silver impurity on the structural,electrical, and optical properties of ZnO nanowires

1, 3, and 5 wt.% silver-doped ZnO (SZO) nanowires (NWs) are grown by hot-walled pulsed laser deposition. After silver-doping process, SZO NWs show some change behaviors, including structural, electrical, and optical properties. In case of structural property, the primary growth plane of SZO NWs is switched from (002) to (103) plane, and the electrical properties of SZO NWs are variously measured to be about 4.26 × 10⁶, 1.34 × 10⁶, and 3.04 × 10⁵ Ω for 1, 3, and 5 SZO NWs, respectively. In other words, the electrical properties of SZO NWs depend on different Ag ratios resulting in controlling the carrier concentration. Finally, the optical properties of SZO NWs are investigated to confirm p-type semiconductor by observing the exciton bound to a neutral acceptor (A⁰X). Also, Ag presence in ZnO NWs is directly detected by both X-ray photoelectron spectroscopy and energy dispersive spectroscopy. These results imply that Ag doping facilitates the possibility of changing the properties in ZnO NWs by the atomic substitution of Ag with Zn in the lattice.     

Microstructure and optical properties of nanocrystalline Cu2O thin films prepared by electrodeposition

Cuprous oxide (Cu₂O) thin films were prepared by using electrodeposition technique at different applied potentials (−0.1, −0.3, −0.5, −0.7, and −0.9 V) and were annealed in vacuum at a temperature of 100°C for 1 h. Microstructure and optical properties of these films have been investigated by X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), UV-visible (vis) spectrophotometer, and fluorescence spectrophotometer. The morphology of these films varies obviously at different applied potentials. Analyses from these characterizations have confirmed that these films are composed of regular, well-faceted, polyhedral crystallites. UV–vis absorption spectra measurements have shown apparent shift in optical band gap from 1.69 to 2.03 eV as the applied potential becomes more cathodic. The emission of FL spectra at 603 nm may be assigned as the near band-edge emission.     

Near infrared emitting Cr3+ doped Zn3Ga2Ge2O10 long persistent phosphor for night vision surveillance and anti-counterfeit applications

The Cr³⁺ doped Zn₃Ga₂Ge₂O₁₀ long persistent phosphor materials were synthesized by solid state reaction method. The crystal structure of the synthesized phosphors are cubic with space group Fd3m. The band gap of the undoped host is about 4.48 eV. The materials show three photoluminescence excitation bands peaked at 260 nm, 412 nm and 580 nm. Due to the broad excitation band, the phosphors can be excited by UV light or visible light or sunlight. The phosphors shows a photoluminescence emission band peaked at 698 nm when excited by UV light. The afterglow emission shows a broad emission band with maximum at 700 nm. The detection of NIR light from the sample was observed by Night Vision Monocular for 24 h after switch off the excitation source. A mechanism is introduced to describe afterglow phenomenon and trap depth was calculated from thermoluminescence curve. As the material emit NIR persistent light, it was used as a secret light source for night vision devices. The developed material was used for tagging, tracking and locating purposes in defence application. The acrylic based paint was prepared to develop long persistent near infrared (NIR) paint, which can be coated on combat vehicle, ship, weapon, helmet, cloth, tent, rock for defence application. The NIR security ink was prepared and demonstrated to prevent counterfeit. Encryption and decryption method of confidential information was presented by using NIR security ink.     

Nano Ca–Mg–Zn ferrites as tuneable photocatalyst for UV light-induced degradation of rhodamine B dye and antimicrobial behavior for water purification

We report the synthesis of Ca-doped Mg–Zn ferrite Mg_0.4Zn_(0.6-x)Ca_xFe₂O₄ nanomaterials with x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6 through citrate precursor approach and their structural, morphological, optical, photocatalytic, and antimicrobial properties were systematically studied. The prepared nanoferrites's cubic spinel structure with an average crystallite size of 15–38 nm was evaluated by the XRD examination. The spherical morphology of these ferrite nanoparticles was seen from scanning electron microscopy (SEM). The observed bands at 560 cm⁻¹ and 406 cm⁻¹ in the FTIR spectra confirmed the spinel structure of the synthesized nanoferrite. The optical study confirmed an optical band gap of 1.60 eV–1.86 eV. The photocatalysis was done for the degradation of rhodamine B dye solution under UV light. All the synthesized nano ferrites displayed a promising antimicrobial potential upon Candida albicans fungi. Mg_0.4Zn_0.1Ca_0.5Fe₂O₄ nanoparticles have a better photocatalytic response (99.5%) for the degradation of rhodamine B dye and show superior antimicrobial activity (96.1%) for the inhibition of Candida albicans fungi.     

Enhanced Sensing Ability of Brush-Like Fe2O3-ZnO Nanostructures towards NO2 Gas via Manipulating Material Synergistic Effect

Brush-like α-Fe₂O₃–ZnO heterostructures were synthesized through a sputtering ZnO seed-assisted hydrothermal growth method. The resulting heterostructures consisted of α-Fe₂O₃ rod templates and ZnO branched crystals with an average diameter of approximately 12 nm and length of 25 nm. The gas-sensing results demonstrated that the α-Fe₂O₃–ZnO heterostructure-based sensor exhibited excellent sensitivity, selectivity, and stability toward low-concentration NO₂ gas at an optimal temperature of 300 °C. The α-Fe₂O₃–ZnO sensor, in particular, demonstrated substantially higher sensitivity compared with pristine α-Fe₂O₃, along with faster response and recovery speeds under similar test conditions. An appropriate material synergic effect accounts for the considerable enhancement in the NO₂ gas-sensing performance of the α-Fe₂O₃–ZnO heterostructures.     

Tin Oxide Nanowires: The Influence of Trap States on Ultrafast Carrier Relaxation

We have studied the optical properties and carrier dynamics in SnO₂ nanowires (NWs) with an average radius of 50 nm that were grown via the vapor–liquid solid method. Transient differential absorption measurements have been employed to investigate the ultrafast relaxation dynamics of photogenerated carriers in the SnO₂ NWs. Steady state transmission measurements revealed that the band gap of these NWs is 3.77 eV and contains two broad absorption bands. The first is located below the band edge (shallow traps) and the second near the center of the band gap (deep traps). Both of these absorption bands seem to play a crucial role in the relaxation of the photogenerated carriers. Time resolved measurements suggest that the photogenerated carriers take a few picoseconds to move into the shallow trap states whereas they take ~70 ps to move from the shallow to the deep trap states. Furthermore the recombination process of electrons in these trap states with holes in the valence band takes ~2 ns. Auger recombination appears to be important at the highest fluence used in this study (500 μJ/cm²); however, it has negligible effect for fluences below 50 μJ/cm². The Auger coefficient for the SnO₂ NWs was estimated to be 7.5 ± 2.5 × 10⁻³¹ cm⁶/s.     

Fabrication of Mg-doped ZnO nanofibers with high purities and tailored band gaps

The tailored doping levels towards the band gap tunability are one of the challenges to push forward the potential application of one-dimensional (1D) ZnO nanostructures in the opto/electric nanodevices. In present work, we reported the exploration of Mg-doped ZnO nanofibers via electrospinning of polyvinylpyrrolidone (PVP), Zn(CH₃COO)₂ (ZnAc) and Mg(CH₃COO)₂ (MgAc), followed by calcination in air. The resultant products were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), and X-ray photoelectron spectroscopy (XPS). The optical measurements (UV–vis) of the Mg-doped ZnO nanofibers suggested that the optical band gaps of the ZnO nanofibers could be tuned from 3.33 to 3.40 eV as a function of the Mg doing levels. This tunability of the band gap of ZnO nanofibers with an intentional impurity could eventually be useful for optoelectronic applications.     

Synthesis, characterization and optical properties of Mg(OH)2 micro-/nanostructure and its conversion to MgO

Magnesium hydroxide (Mg(OH)₂) micro- and nanostructures have been synthesized by a single step hydrothermal route. Surface morphology analysis reveals the formation of micro- and nanostructures with varying shape and size at different synthesis conditions. Structural investigations by X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirm that the synthesized material is Mg(OH)₂ with hexagonal crystal structure. An optical band gap of 5.7 eV is determined for Mg(OH)₂ nanodisks from the UV–vis absorption spectrum. A broad emission band with maximum intensity at around 400 nm is observed in the photoluminescence (PL) spectra of Mg(OH)₂ nanodisks at room temperature depicting the violet emission, which can be attributed to the ionized oxygen vacancies in the material. Furthermore, Mg(OH)₂ has been converted to MgO by calcination at 450 °C. Optical studies of the MgO nanodisks have shown an optical band gap of 3.43 eV and a broadband PL emission in the UV region. Mg(OH)₂ and MgO nanostructures with wide-band gap and short-wavelength luminescence emission can serve as a better luminescent material for photonic applications.     

Annealing temperature and environment effects on ZnO nanocrystals embedded in SiO2: a photoluminescence and TEM study

We report on efficient ZnO nanocrystal (ZnO-NC) emission in the near-UV region. We show that luminescence from ZnO nanocrystals embedded in a SiO₂ matrix can vary significantly as a function of the annealing temperature from 450°C to 700°C. We manage to correlate the emission of the ZnO nanocrystals embedded in SiO₂ thin films with transmission electron microscopy images in order to optimize the fabrication process. Emission can be explained using two main contributions, near-band-edge emission (UV range) and defect-related emissions (visible). Both contributions over 500°C are found to be size dependent in intensity due to a decrease of the absorption cross section. For the smallest-size nanocrystals, UV emission can only be accounted for using a blueshifted UV contribution as compared to the ZnO band gap. In order to further optimize the emission properties, we have studied different annealing atmospheres under oxygen and under argon gas. We conclude that a softer annealing temperature at 450°C but with longer annealing time under oxygen is the most preferable scenario in order to improve near-UV emission of the ZnO nanocrystals embedded in an SiO₂ matrix.     

Enhanced UV photosensitivity from rapid thermal annealed vertically aligned ZnO nanowires

We report on the major improvement in UV photosensitivity and faster photoresponse from vertically aligned ZnO nanowires (NWs) by means of rapid thermal annealing (RTA). The ZnO NWs were grown by vapor-liquid-solid method and subsequently RTA treated at 700°C and 800°C for 120 s. The UV photosensitivity (photo-to-dark current ratio) is 4.5 × 10³ for the as-grown NWs and after RTA treatment it is enhanced by a factor of five. The photocurrent (PC) spectra of the as-grown and RTA-treated NWs show a strong peak in the UV region and two other relatively weak peaks in the visible region. The photoresponse measurement shows a bi-exponential growth and bi-exponential decay of the PC from as-grown as well as RTA-treated ZnO NWs. The growth and decay time constants are reduced after the RTA treatment indicating a faster photoresponse. The dark current-voltage characteristics clearly show the presence of surface defects-related trap centers on the as-grown ZnO NWs and after RTA treatment it is significantly reduced. The RTA processing diminishes the surface defect-related trap centers and modifies the surface of the ZnO NWs, resulting in enhanced PC and faster photoresponse. These results demonstrated the effectiveness of RTA processing for achieving improved photosensitivity of ZnO NWs.     

Influential diamagnetic magnesium (Mg2+) ion substitution in nano-spinel zinc ferrite (ZnFe2O4): Thermal,structural, spectral,optical and physisorption analysis

Nano-spinel zinc ferrites (ZnFe₂O₄) with substitution of diamagnetic magnesium (Mg²⁺) ions were synthesized using solution-gelation (sol-gel) self ignition route. The thermal, structural, spectral, optical and N₂-physisorption properties of the prepared Zn–Mg ferrite nanoparticles were analyzed by standard characterization techniques. The temperature dependent spinel phase formation and percentage weight loss was studied by thermogravimetric and differential thermal analysis (TG-DTA). The analysis of the room temperature X-ray diffraction (XRD) patterns showed the formation of cubic spinel structure with single phase in the Zn–Mg ferrites. The crystallite size decreasing from 27 nm to 20 nm with Mg²⁺ substitution confirmed the nanocrystalline formation of the Zn–Mg ferrites. The two characteristics vibrational modes of interstitial sub-lattice sites corresponding to the spinel structure were observed within the desired wavelength range of the FT-IR spectra. The optical band gap values estimated from the UV–Visible data analysis is found to be in the scope of 1.96 eV–2.39 eV. The photoluminescence (PL) spectra showed the broader emission band in the visible region (around 525 nm) for all the samples of Zn–Mg ferrites. The BET isotherms were recorded by the N₂ adsorption-desorption and the surface area, pore volume, average pore radius etc surface parameters were deduced. The BET surface area and average pore radius values were obtained in the range of 5.6–24.8 m²/gm and 2.61–4.52 nm respectively.